/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.dtstack.taier.develop.sql;

import java.io.Serializable;

public class Pair<K,V> implements Serializable {

    /**
     * Key of this <code>Pair</code>.
     */
    private K key;

    /**
     * Gets the key for this pair.
     * @return key for this pair
     */
    public K getKey() { return key; }

    /**
     * Value of this this <code>Pair</code>.
     */
    private V value;

    /**
     * Gets the value for this pair.
     * @return value for this pair
     */
    public V getValue() { return value; }

    /**
     * Creates a new pair
     * @param key The key for this pair
     * @param value The value to use for this pair
     */
    public Pair(K key,V value) {
        this.key = key;
        this.value = value;
    }

    /**
     * <p><code>String</code> representation of this
     * <code>Pair</code>.</p>
     *
     * <p>The default name/value delimiter '=' is always used.</p>
     *
     *  @return <code>String</code> representation of this <code>Pair</code>
     */
    @Override
    public String toString() {
        return key + "=" + value;
    }

    /**
     * <p>Generate a hash code for this <code>Pair</code>.</p>
     *
     * <p>The hash code is calculated using both the name and
     * the value of the <code>Pair</code>.</p>
     *
     * @return hash code for this <code>Pair</code>
     */
    @Override
    public int hashCode() {
        // name's hashCode is multiplied by an arbitrary prime number (13)
        // in order to make sure there is a difference in the hashCode between
        // these two parameters:
        //  name: a  value: aa
        //  name: aa value: a
        return key.hashCode() * 13 + (value == null ? 0 : value.hashCode());
    }

     /**
      * <p>Test this <code>Pair</code> for equality with another
      * <code>Object</code>.</p>
      *
      * <p>If the <code>Object</code> to be tested is not a
      * <code>Pair</code> or is <code>null</code>, then this method
      * returns <code>false</code>.</p>
      *
      * <p>Two <code>Pair</code>s are considered equal if and only if
      * both the names and values are equal.</p>
      *
      * @param o the <code>Object</code> to test for
      * equality with this <code>Pair</code>
      * @return <code>true</code> if the given <code>Object</code> is
      * equal to this <code>Pair</code> else <code>false</code>
      */
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
         if (o instanceof Pair) {
             Pair pair = (Pair) o;
             if (key != null ? !key.equals(pair.key) : pair.key != null) return false;
             if (value != null ? !value.equals(pair.value) : pair.value != null) return false;
             return true;
         }
         return false;
     }
 }